1. Field of the Invention
The present invention relates to a light source driver, a light source device, a light scanning device and an image forming apparatus; more specifically, it relates to a light source driver that outputs driving signals to drive a plurality of light-emitting bodies, a light source device having the light source driver, a light-scanning device having the light source device and an image-forming apparatus including the light-scanning device.
2. Description of the Related Art
In image recording of electronic photography, an image-forming apparatus using a laser is widely used. In this case, the image-forming apparatus includes a light-scanning device, and a method to scan a surface to be scanned with laser beams using a polygon scanner (for example, a polygon mirror) in an axial direction of a photosensitive drum while rotating the drum to form a latent image is commonly used. In the field of electronic photography as such, in order to improve image quality and operability, an image having higher density and high-speed image output is required from the image-forming apparatus.
Therefore, a method to simultaneously scan a plurality of adjacent lines using a plurality of light beams is proposed.
For example, in JP2000-012973A, an image-forming apparatus having light-emitting elements each including a first electrode and a second electrode is disclosed. The light-emitting elements are disposed two-dimensionally within a long-shaped area and each light-emitting element includes a first wiring line that is connected to the first electrode and a second wiring line that is connected to the second electrode. The first wiring lines as row wiring lines formed in a long side direction and the second wiring lines as column wiring lines formed in a short side direction are connected in a matrix shape to form a light-emitting element array. The light-emitting element array disposed two-dimensionally is divided into a plurality of blocks, each of which is capable of independently driving. The row wiring lines and the column wiring lines are applied to each block of the light-emitting element array. Pull-out lines are pulled out from the row wiring lines in the column direction.
In addition, in JP2002-314191A, a light-emitting element array including a plurality of light-emitting elements disposed on a base substrate, a plurality of electrode pads disposed on the base substrate and a plurality of wiring lines that individually connect between the plurality of light-emitting elements and the plurality of electrode pads is disclosed. In the light-emitting element array, the floating capacitance of the plurality of wiring lines is approximately the same.
Incidentally, in recent years, it is known that a surface light-emitting laser element may be used as a light source of an image-forming apparatus.
For example, in JP2002-217488A, a surface light-emitting laser element including a multiple quantum well structure part between an active layer and a pair of distributed Bragg reflectors disposed to face each other via the active layer is disclosed. In the surface light-emitting laser element, a first electrode to apply a current to the active layer and a second electrode to apply an electric field to the multiple quantum well structure part are independently disposed. The surface light-emitting laser element has variable oscillation wavelength and changes a refractive index of the multiple quantum well structure part by applying an electric field to the multiple quantum well structure part through the second electrode. In the surface light-emitting laser element, GaInNAs mixed crystal is used as a material for a well layer of the multiple quantum well structure part.
In recent years, an image-forming apparatus has been used in simplified printing as an on-demand printing system and accompanying that, an image-forming apparatus of low price and superior image quality is required.